(二)面板的凸起、下陷或断裂在日常生活中,用手压一根长的薄木条,用力不大,就能压弯;再一用力,它就折断。木条越长,越容易压弯,我们称木条越细(薄)长,越“不稳定”。已知1梁处面板弧度与水平的夹角φ=8°,而琴弦与水平夹角γ=10°。忽略面板到弦枕距离(20mm)的影响,可以把对弦枕的拉力看作是作用在面板两端的压力(即轴向压力)。扬琴面板厚度在5～9mm范围内,与长度相比,可视为工程材料(包括拱形)中的薄壁构件。当薄壁构件承受轴 (B) the panel raised, sagging or fracture In daily life, hand pressing a long thin wood, with little effort, you can bend; another force, it breaks. The longer the wood, the easier it is to bend. We call the thinner (thinner) the wood, the more “unstable” it is. It is known that the angle between the radian and the horizontal of the panel at the beam is φ = 8 °, while the angle between the strings and the horizontal is γ = 10 °. Ignoring the influence of the panel to the chord length (20 mm), the pull on the chord can be thought of as acting on the pressure across the panel (ie axial pressure). Dulcimer panel thickness in the range of 5 ~ 9mm, compared with the length, can be considered as engineering materials (including arched) thin-walled components. When thin-walled components bear the shaft